Connection speed of sourceforge

Connection speed of the Godaddy server is generally slower than the 1&1 server. It was test proven from Europe and China. However, when connecting to downloads.sourceforge.net, Godaddy is faster.

The Godaddy server automatically chooses the mirror site softlayer.dl.sourceforge.net, and the average speed is 8.55M/s. The 1&1 server chooses dfn.dl.sourceforge.net, and the speed is 70K/s. When I force the 1&1 server to download from softlayer.dl.sourceforge.net, the speed does not improve. It is slower even than I download from my PC via ADSL.

I do not know why there is such a big difference in connection speed from different locations.